BEOL Compatible Extremely Scaled Bilayer ITO/IGZO Channel FET with High Mobility 106 cm2/V.s

In this work, we report an approach to significantly improve the electrical performances of a bottom-gated Indium-Gallium-Zinc oxide (IGZO) FET by introducing a thin layer of tin doped Indium oxide (ITO). We demonstrate low thermal budget ITO/IGZO FETs, with extremely scaled channel thickness and length of 4 nm and 50 nm respectively, achieving highest $\mathrm{I}_{\text{ON}}770\mu \mathrm{A}/\mu \mathrm{m}$, highest $\mu_{\text{eff}}$ of 106 $\text{cm}^{2}/\mathrm{V}\cdot \mathrm{s}$, and low SS of 92 mV/decade. We also investigate the role of ultra-thin ITO in defect passivation to enhance FET performance.